1. Field of the Invention
The present invention relates to a liquid crystal display device and more particularly to an active matrix type liquid crystal display device having a non-display region such as, for example, an opening in a part of the display region thereof.
2. Background Art
Active matrix type liquid crystal display devices include at least a thin film transistor which is turned on by a scanning signal from a gate signal line and a pixel electrode which is supplied with a video signal from a drain signal line through the turned-on thin film transistor in each of pixel regions surrounded by, for example, a plurality of gate signal lines extending in the x-direction and arranged in parallel in the y-direction and a plurality of drain signal lines extending in the y-direction and arranged in parallel in the x-direction on a surface on the liquid crystal side of one of a pair of substrates which are disposed to face each other with liquid crystal interposed therebetween.
One of the substrates is fixed to the other substrate with a sealing material which is formed so as to surround a display region composed of the assembly of the pixel regions and functions to seal the liquid crystal therein. Spacers are generally interposed in a scattered manner in the display region and the forming region of the sealing material between the substrates in order to uniform the layer thickness of the liquid crystal.
Among such liquid crystal display devices, a liquid crystal display device applied, for example, to amusement equipment has been known in which an opening (non-display region) formed of a through hole is formed in a part of the display region in each of the substrates. Such a liquid crystal display device is disclosed in, for example, JP-A-2005-46352.
In this case, although not described in detail in JP-A-2005-46352, the opening is formed in a liquid crystal display region, and therefore a new sealing material (this sealing material is referred to as inner sealing material, whereas the conventional sealing material formed on the outer circumference of the substrates is sometimes referred to as outer sealing material) has to be formed so as to surround the opening between the substrates to seal liquid crystal therein.
JP-A-2006-323141 is another patent document relating to the invention although it does not include the inner sealing material. JP-A-2006-323141 discloses a technique of arranging spacers referred to as so-called columnar spacers in the forming region of the outer sealing material and describes that the columnar spacers function as a base for placing a mask in forming an alignment film by vapor deposition.